Chrysophyllum Albidum extract as a new and green protective agent for metal

Abstract

ABSTRACT Gravimetric measurements and potentiodynamic polarization techniques were employed to investigate the protective performance of the metal in 1 M HCl and 0.5 M H2SO4 solutions by the C. albidum leaf extract at different concentrations (400-1600 mg/L) and time periods (1-4 days). The results showed the highest protection ability of over 96-97%, with inhibition increasing with higher extract concentrations. Polarization studies indicated a mixed inhibition mechanism, reducing both anodic dissolution and cathodic hydrogen evolution rates. Gas chromatography–mass spectrometry (GC–MS) analysis identified major organic constituents in the extract. Thermodynamic data fit the Langmuir isotherm model, suggesting chemisorptive adsorption of inhibitor molecules on the mild steel surface. Computational methods, including density functional theory (DFT), molecular dynamics simulations, and quantum chemical calculations, provided insight into inhibitor-metal interactions and adsorption behaviour at the molecular level. Overall, the study establishes C. albidum leaf extract as an effective, sustainable alternative to commonly used toxic chromate and phosphate inhibitors. It performs competitively even at low concentrations and in environments. The promising green inhibition properties, combined with the extract's nontoxicity and abundance from a natural source, suggest its potential as a cost-effective corrosion protection solution, especially for applications in developing economies.